Williams, Pearl Ravner
and United States. Bureau of Labor Statistics.
Price Perspective: 1965, 1966, 1967 : Bulletin of the United States Bureau of Labor Statistics, No. 1543 ,
Washington, D.C:
For sale by the Supt. of Docs., U.S. G.P.O.,
May 1968, https://fraser.stlouisfed.org/title/4816,
accessed on May 24, 2018.